<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>tab-JQ</title>
    <style>
        * {margin: 0; padding: 0; list-style: none;}
        #wrap {width: 600px; margin: 100px auto 0; overflow: hidden;}
        #tit {height: 30px;width: 600px;}
        #tit span {float: left; height: 30px; line-height: 30px; width: 200px; font-size: 20px; text-align: center; color: #ccc;background: green;}
        #con li{display: none; height: 200px; width: 600px; background: pink;font-size: 100px;line-height: 200px;text-align: center;}
        #tit span.select {background: red; color: #ccc;}
        #con li.show {display: block;}
    </style>
    <script src="lib/jquery/jquery.js"></script>
</head>
<body>
    <div id="wrap">
        <div id="tit">
            <span class="select">标题1</span>
            <span>标题2</span>
            <span>标题3</span>
        </div>
        <ul id="con">
            <li class="show">内容111</li>
            <li>内容222</li>
            <li>内容333</li>
        </ul>
    </div>
    <script>
        $('#tit span').click(function() {
            var i = $(this).index();//下标第一种写法
            //var i = $('tit').index(this);//下标第二种写法
            $(this).addClass('select').siblings().removeClass('select');
            $('#con li').eq(i).show().siblings().hide();
        });
    </script>
</body>
</html>